From mboxrd@z Thu Jan 1 00:00:00 1970 From: Catalin Marinas Subject: Re: [RFC PATCH 0/5] Add smp booting support for Qualcomm ARMv8 SoCs Date: Fri, 10 Apr 2015 11:05:29 +0100 Message-ID: <20150410100529.GA6854@e104818-lin.cambridge.arm.com> References: <1428601031-5366-1-git-send-email-galak@codeaurora.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from foss.arm.com ([217.140.101.70]:55044 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753963AbbDJKFh (ORCPT ); Fri, 10 Apr 2015 06:05:37 -0400 Content-Disposition: inline In-Reply-To: <1428601031-5366-1-git-send-email-galak@codeaurora.org> Sender: linux-arm-msm-owner@vger.kernel.org List-Id: linux-arm-msm@vger.kernel.org To: Kumar Gala Cc: linux-arm-msm@vger.kernel.org, devicetree@vger.kernel.org, abhimany@codeaurora.org, will.deacon@arm.com, linux-kernel@vger.kernel.org, arm@kernel.org, linux-arm-kernel@lists.infradead.org On Thu, Apr 09, 2015 at 12:37:06PM -0500, Kumar Gala wrote: > This patch set adds support for SMP boot on the MSM8x16 family of Qualcomm SoCs. > > To support SMP on the MSM8x16 SoCs we need to add ARMv8/64-bit SCM interfaces to > setup the boot/release addresses for the secondary CPUs. In addition we need > a uniquie set of cpu ops. I'm aware the desired methods for booting secondary > CPUs is either via spintable or PSCI. However, these SoCs are shipping with a > firmware that does not support those methods. And the reason is? Some guesses: a) QC doesn't think boot interface (and cpuidle) standardisation is worth the effort (to put it nicely) b) The hardware was available before we even mentioned PSCI c) PSCI is not suitable for the QC's SCM interface d) Any combination of the above I strongly suspect it's point (a). Should we expect future QC hardware to do the same? You could argue the reason was (b), though we've been discussing PSCI for at least two years and, according to QC press releases, MSM8916 started sampling in 2014. The only valid reason is (c) and if that's the case, I would expect a proposal for a new firmware interface protocol (it could be PSCI-based), well documented, that can be shared with others that may encounter the same shortcomings. -- Catalin From mboxrd@z Thu Jan 1 00:00:00 1970 From: catalin.marinas@arm.com (Catalin Marinas) Date: Fri, 10 Apr 2015 11:05:29 +0100 Subject: [RFC PATCH 0/5] Add smp booting support for Qualcomm ARMv8 SoCs In-Reply-To: <1428601031-5366-1-git-send-email-galak@codeaurora.org> References: <1428601031-5366-1-git-send-email-galak@codeaurora.org> Message-ID: <20150410100529.GA6854@e104818-lin.cambridge.arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Thu, Apr 09, 2015 at 12:37:06PM -0500, Kumar Gala wrote: > This patch set adds support for SMP boot on the MSM8x16 family of Qualcomm SoCs. > > To support SMP on the MSM8x16 SoCs we need to add ARMv8/64-bit SCM interfaces to > setup the boot/release addresses for the secondary CPUs. In addition we need > a uniquie set of cpu ops. I'm aware the desired methods for booting secondary > CPUs is either via spintable or PSCI. However, these SoCs are shipping with a > firmware that does not support those methods. And the reason is? Some guesses: a) QC doesn't think boot interface (and cpuidle) standardisation is worth the effort (to put it nicely) b) The hardware was available before we even mentioned PSCI c) PSCI is not suitable for the QC's SCM interface d) Any combination of the above I strongly suspect it's point (a). Should we expect future QC hardware to do the same? You could argue the reason was (b), though we've been discussing PSCI for at least two years and, according to QC press releases, MSM8916 started sampling in 2014. The only valid reason is (c) and if that's the case, I would expect a proposal for a new firmware interface protocol (it could be PSCI-based), well documented, that can be shared with others that may encounter the same shortcomings. -- Catalin